1. Field of the Invention
The present invention relates to a dishwasher.
2. Discussion of the Related Art
Generally, a dishwasher is an apparatus for automatically washing and drying tableware by injecting water and detergent on the tableware. A dishwasher according to a related art is explained by referring to the attached drawings.
FIG. 1 is a perspective view of a dishwasher according to a related art and FIG. 2 is a cross-sectional view of a rack assembly of a dishwasher according to a related art.
Referring to FIG. 1 and FIG. 2, a dishwasher according to a related art mainly consists of a cabinet 4 having a large open front side, a washing chamber 2 provided in the cabinet 4, and a door 6 opening closing the open front side of the cabinet 4.
Upper and lower racks 10 and 12 on which tableware is put are provided in the washing chamber 2, and top and bottom nozzles 14 and 16 injecting water via injection holes are rotatably provided under the upper and lower racks 10 and 12, respectively.
A sump (not shown in the drawing) is provided under the washing chamber 2 to collect water therein. A pump (not shown in the drawing) pumping water to the top and bottom nozzles 14 and 16 and a heater assembly (not shown in the drawing) for heating water held in the sump are provided in the sump.
Moreover, a blower assembly 6a for bowing out humid air in the dishwasher in progress and a detergent box assembly 6b storing a detergent are provided to an inside of the door 6. And, a gasket (not shown in the drawing) is provided to an inner circumference of the door 6 to make the door adhere closely to cabinet 4 when the door 6 is closed.
Meanwhile, the upper and lower racks 10 and 12 are provided to move back and forth in the washing chamber 2. Specifically, wheels 12a are attached to a bottom of the lower rack 12 so that the lower rack 12 can be drawn outside the washing chamber 2 when the door 6 is fully open.
A plurality of first and second guide rollers 22a and 22b are provided to both sidewalls of the washing chamber 2, and a guide rail 24 is provided between of the first and second guide rollers 22a and 22b to slide back and forth. Moreover, a groove 24a is formed at the guide rail 24, and upper and one of lower rollers 26a and 26b fixed to upper and lower portions of each lateral side of the upper rack 10 is inserted in the corresponding groove 24a. 
In this case, when the upper rack 10 is installed at a relatively low position in order to put large-sized tableware on the upper rack 10, the upper roller 26a is inserted in the groove 24a of the guide rail 24. When the upper rack 10 is installed at a relatively high position in order to put small-sized tableware on the upper rack 10, the lower roller 26b is inserted in the groove 24a of the guide rail 24.
However, in the related art dishwasher, the upper rack is taken off from the guide rail and then fitted thereto again in order to adjust the installation position of the upper rack, thereby causing inconvenience in use.